I have many simple projects running that will submit forum profiles with submissions of 5 +- 2 per day before it pauses . I have noticed that some submissions reach 30+ without looking like stopping. If I edit the project while it is running it seems to take notice of the submission count and pause shortly after editing.
Many users would probably not notice this if they have high numbers of submissions set but for a small amount it becomes obvious.
Also, I have noticed that if I edit a project (after it has paused from reaching maximum submissions for the day) it will sometimes restart even though the number of submissions parameter is not changed.